1. Field of the Invention
The present invention relates to a laser module for reading optical codes.
2. Discussion of Prior Art
Known optical code readers can essentially be divided into readers wherein the entire code width is simultaneously illuminated, as through an array of LEDs, and the diffused light is simultaneously collected and detected, as by an array of linear or matrix sensors (“imaging” of the optical code), and readers wherein a laser beam sweeps a certain angle so that a laser spot scans the optical code (“flying spot”), and the diffused light is collected and detected by photo-detecting elements of the photodiode and/or CCD and/or C-MOS type.
The readers of the second type include a laser module for reading optical codes having essentially a source for generating a laser beam of predetermined size and shape, means for generating a scan of the laser beam on the optical code to be read, means for collecting at least a portion of the light diffused by the code, and photo-detecting means for detecting the collected light and converting the detected luminous power into an electrical signal reproducing as accurately as possible the reflectance modulations of the elements forming the code.
Known laser modules are of the retro-reflective type, that is, they are such that the field of view framed by the light collecting optics coincides, instant by instant, with that framed by the scan means. In other words, the apertures used for scanning the laser beam along the code to be read are the same used for collecting the diffused light towards the detection optics.
The technical problem at the basis of the present invention is that of providing a compact laser module.